Have you ever wondered what makes some women give birth to their babies at week 38 and others do it at week 41? Have you ever wondered what is the sign that indicates that the baby should be born? Because there are those who think that it is the mother’s body that says that it is time and there are those who think that it is the baby’s thing and, under normal conditions, it is the latter who are right .
Researchers at the Southwestern Medical Center of the University of Texas (USA) have discovered with their experiments where the signal that starts labor comes from, that is, they have found the beginning of everything, the red “Delivery” button, and not it is in the mother, but in the baby, who is born thanks to his lungs .
Apples do not fall until they are ripe
When does an apple fall? Well, when it is mature. Some before, others after. The same thing happens with babies: they are not born until they are ready and that is why there is more and more reluctance when it comes to causing births in this or that week. And when is a baby ready to be born? Well, when it is ready to live outside, when its organs are mature enough and, above all, when it is able to breathe. That is to say, it is the lungs that say when they will be able to perform their function perfectly and it is they that say when a baby may or may not yet be born.
And when are they ripe? Well, by the time they have enough surfactant . Pulmonary surfactant is a substance that we all have in our lung alveoli whose mission is to allow breathing. To delve further into the subject, the alveoli are like sachets that empty when exhaling and since at that moment they are practically without air, they could collapse (join one wall with another) and make the next inspiration difficult. Well, the surfactant prevents that from happening.
The SRC-1 and SRC-2 proteins
For the discovery they did several experiments with mice. With them they found two proteins, SRC-1 and SRC-2 , that control lung surfactant genes. They are not activated until moments before birth, thus preparing the lungs for external life and promoting the onset of labor.
Another factor that affects the time of delivery is platelet activator (PAF) . This factor increases the concentration of platelets in the fetus, also to prepare it for its baby life. However, it seems that it does not affect as much at the time of giving the signal because when some mice had this factor reduced, delivery happened about 12 hours later (which is equivalent to one more week of pregnancy in humans).
Now, what happened when they inhibited the function of the two proteins mentioned and, consequently, the lungs did not have enough surfactant? Deliveries were delayed an average of 38 hours, which is equivalent to 3-4 weeks of pregnancy in a woman .
And how does all this happen?
In the last days of maturation of the fetus, the SRC-1 and SRC-2 proteins begin to cause increased secretion of surfactant in the lungs and, at the same time, the platelet activating factor is activated. This increase is reflected in the amniotic fluid , where the concentration of these substances increases. The uterus must be sensitive to it, because the consequence is that an inflammatory response is produced in it and thus labor begins.
In any case, to better understand this process, the researchers have already explained that they are going to study everything that happens afterwards. That is, they know what triggers labor, but they want to understand well how the message passes from the fetus to the mother.
Could this help prevent premature births?
That is the intention. Most neonatal deaths are in premature babies . In addition, being born earlier sometimes implies having maturational problems, needing some interventions and, ultimately, being born with a more or less clear disadvantage compared to full-term babies. Anything that can be done to avoid it is welcome.
The researchers are suggesting that thanks to their discovery they will be able to know exactly how labor is triggered and thus, in the future, be able to control the levels of these proteins in some way to avoid premature births. Come on, that in the same way that they delayed the births of the mice, they could do the same, perhaps, with the humans. Obviously, this is nothing more than a hypothesis … then it will be necessary to see if there is any implication to this solution, that is, to see that the remedy is no worse than the disease.
Meanwhile, while all that research comes in, ordinary mortals benefit by increasing our general culture. Now we know how labor is triggered .
Via | The Journal of Clinical Investigation
Photos | iStock, Thinkstock
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